Back spacer for typewriters



sept. z, 1924. 1,507,353

O. A. HOKANSON BACK SPACER FOR TYPEWRITERS Filed Aug. 25 1921 2Shoal-Shut 2 Patented Sept. 2, 1924.

`UNITED STATES ATENT kOTTO A. HOKANSON, OF XVOODSTOCK, ILLINOIS,A.SSIG-NO'R TO "WOODSTOCK TYPE- WRITER COMPANY, 0F W'OGDSTOCK, ILLINS,.A CORPORATION OF ILLINOIS.

BACK SPACER FOR TYPEWRITERS Application led August 25,41921.

To all iti/1.0m t 772m/ concern.'

' Be it known that I, OTTO A. I-IoKANsoN, a citizen ofA the UnitedStates, residing at 'Woodstocln in the county of McHenry and State ofIllinois, have invented certain new and useful Improvements in BackSpacers for Typewriters, of which the following is a. specification.

This invention relates to mechanism for moving the platen carriage of atypewriter in a reverse direction, a letter space at a time, and isespecially applicable to typewriters in which the platen carriage ismovable into a compacted position.

The invention has for its object the provision of mechanism of the classnamed which shall be ofimproved construction and operation. It isexemplified in the combination and arrangement of parts shown in ,ftheaccompanying drawings and described in the followingspecification, andis more particularly pointed out in the appended claims. I, In thedrawings- Fig. 1 is a vertical sectional view of a portion of atypewriter showing one embodiment of the present invention appliedthereto; v

2 is a fragmentary view of a portion of the typewriter illustrated inFig. 1 and shows the back spacer mechanism in top plan; and e y Fig. 3is a vertical section of a portion of a typewriter showing the backspacer mechanism in elevation.

In the figure of the drawings, the numeral 10 designates the main orbase frame of a typewriter having arms 11 pivoted at 12 thereon andcarrying a platen carriage frame 13. Ways 14 are formed on the frame 13and a platen carriage 15 is arranged to travel along the ways 14C. Anescapement wheel 16 is journaled on the frame 13 and is provided with apinion 17 which meshes with a rack 18` for controlling the movement ofthe platen carriage. Any suitable es- `capemeut mechanism may beprovided for the escapement wheel 16. A back spacing key 19 is pivotedat 2O on the frame 10 and is provided with an upwardly extendin arm 21arranged to engage one arm 22 of a bell crank lever 23 pivoted at 24 ona bracket '25 supported on the frame 10. The other arm 26 of the bellcrank 23 is pivotally connected at 27 to one end of a link 23. Theopposite end of the link 28 is pivoted at 29 Serial No. 425,330.

to a crank arm 30 having` a slot 3l arranged to engage a screw 32 forboth sliding and rotary movement. rIhe screw 32 is supported on abracket 33 in av position concentric with the axis of the sprocket wheel16 when the platen lcarriage frame is in its operating position.

A spring 34 normally draws the link 2S to the right and rearwardly. asviewed in Fig. 2. Thev movement of the link to the right is limited bythe end of the slot 317 and the rearward movement is limited by a pin 35secured Ato the link in position to strike the edge of the crank arm 30.l When the back spacing key is depressed the link 28 will be movedto theleft causing` the slot 31 to slide on the screw The pivotal connection29 between the link 28 and the crank arm 30 is extended upwardly to alevel with the teeth on the ratchet. wheel 16. The movement of the link28 to the left will 'bring` the pin 29 into enga-gement with one withthe screw 32 further movement ofthe e link 28 to the left will cause thecrank arm 3G and the pin 29 to rotate about the axis of the screw 32 ina clockwise direction, as viewed in Fig. 2, carrying with it theescapement wheel 16. Since the screw and escapement wheel are concentricwith. one another the pin 29 will travel about the same center as thetooth with which itiis engaged. The movement of the pin 29 is limited bya lug 36 bent downwardly from the end of thecrank arm 39 which engages astop 37 projecting from the bracket 33. The movement is suflicient torotate the escapement wheel an amount corresponding to one letter spaceand the escaneinent wheel will, of course, be retained in the positionin which it is rotated by the escapement dogs. Since the cscapementwheel is moved in a reverse direction to its letter fcedino' movementthe platen carriage will be spaced barkwardly. one letter `space foreach operation of the back spacing kev. A spring is provided for theback spacinokev to return it to its uppermost position after each'operation thereof.

It will be seen that the back spacing mechanism is'mounted entirely onthe main frame of the machine and does not .in any way interfere Awiththe folding movement ofthe platen carriage frame. The movement of thefra-me into its operating position automatically brings the escapementwheel into position to co-act with the back spacing ,pin 29.

I claim:-

l. A typewriter comprising a pair of relatively movable framey par-ts, aplaten carriage having escapement mechanism monnt ved on one of saidparts, and -back spacing mechanism for said platen carriage mounted onthe other of said parts, said back. spacing mechanism being lpositionedto cooperate with `said escapement .mechanism when said platen .carriageis kin operating posii tion.

2. A typewriter comprising a main frame, a platen carriage trame-pivotally -mounted Q11 main frame and having escapement mechanismthereon, and back spacing mechanismon said main frame, said backsparcing .mechanism having. a member arranged to engage the escapementmechanism for back =,spacing voperations when said platen carriage frameis in operating position.

23. A typewriter ycomprising a Amain frame, a platen carriage framepiyotally ,mounted thereon, an escapement wheel mounted on said platencarriage frame, and back spacing mechanism y0n said .main frame, saidback .spacing ymechanism having a contact member extending linto aAposition to cooperateI with said -escapement Wheel when said platencarriage frame is in operating position. 4. The combination with anescapement wheel of a typewriter, of back-spacing mechanism arranged ,tocooperate -withsa'id wheel, said back spacing mechanism having a contact.member for engaging .a tooth of said wheel the contact number -beingprovided with a .shifting pivotal connection with the axis of saidwheel, and means for mpving said member ,into engagement -With .saidwheel and subsequently rrotating said member about the .axis `of saidwheel to imparta L,back spacing movement to said wheel.

5. The combination fwit-h an escapement wheel of a typewriter, of backspacing mechanism for .said .typewriterL comprising `a crank arm .havingmeans thereon for engaging a toothof said wheel, and means for 'moving.said Iarm.radially osaid wheel to bring saidLen-gaging means intocontact with said wheel .and for .subsequently revolving JSaid crank,arm .about the axis of .said wheel .to impar-t a back spacing movementto l.said

wheel.

v6. .Back .spacing .mechanism for va typewriter comprising a crank armhaving a .sliding pivotal support, and means v*for slid'- .ing said armyo n its support and subsequently .rotating Ysaid .arm thereon.

k7. `Back .spacing mechanism for ,a typewriter 'having .an escapementwheel, said mechanism comprising a crank arm having nsupport. v n

`Wheel, said crank arm being to.'

a `pivotal .support coaxial with said @Wheel and arranged to slide onsaid support, and Va link connected with said crank arm for moving saidcrank arm in the .direction of the .length :thereof to Abring said larminto cooperative relation with said escapement wheel, said linkbeingarranged to move said arm upon its pivotal support subsequent to saidengagement for imparting a back spacing movement to said escapementwheel.

8. A typewriter .comprising a pair -oif frame members movable relativetoone *fanother, an escapement wheel carried by one' of said members andback Vspacing mechanism vcarried by the other of s aid members., saidback spacing mechanism comprising a crank arm having a pivotal support Ic o-gnrlial with said escapement wheel when said .escapement wheel isfin operating posi 'om means on said @R21-nk ,ann 'for .engaging ,saidescapement wheel fbut normally out `of rthe path thereof, said armbeing-slidable 'upon its pivotal support for bringing psaid.engaggingmeans into cooperative relatnevlth said escapement wheel, and ymeansiorslid- .ing saidarm on its y'suppnt and ,for `sulpsequently rotatingsaid varm to impart a back spacing movement tosaid escapemgent wheel.

9. Back spacing lmechanism Icomjprising a Crank arm .having a .pivotalSu ,portand a longitudinal slot engaging Sai,` '7;support, a ,linkpivoted Vto said lcrank arm, YAa .stop yfor limiting the .movement :ofsaid ,arm and llink trelative yto .one another, .and a spring ar rangedto hold said link and crank arm rin ,a position limited by said stoprandby oneend o ksaid slot.

l0. Back spacing Kmechanism comprising ,a link having aV crank armpivotallyQllXlected thereto, a sliding Apivotal .support torthe-opposite end of said .cranica-rm, means. vfor limiting the` rotarymovementof said crank arm upon its pivot, a, .spring for 'holding saidcrank arm at the limitingpoSiliQns of its pivotal and slidingmovement,and .means tor moving said link `to slide said ,crank arm yto,the opposite end of itssliding movement and subsequently imparta rotarymovement .to said crank .arm about its pivot.

l1. A typewriter having .anesca nt wheel, back spacing mechanism.therefor comprising a crank ,arm having a co-axial ,with said,.escapement slide in ,the direction of the-Llength thereof upon itspivotal Support, a .Contact member carried lby said :crank ,arm for.engaging the teeth of said .esca-pement wheel, .a linkpivotallyconnected with said crankarm, for limi-ting .the movement `ofSaidcrankarm about 'its .pivotal ,support -in one d'inection, resilientmeans for holding ysaid crank ,arm

in a position with-said contact membernatnf the path of the teeth onsaid escapement wheel, and means for moving said link against thetension of said resilient means to first slide said link on its pivotalsupport to bring said contact member into engagement with a tooth onsaid wheel, subsequent movement of said link swinging said crank arm andcontact member about the axis of said escapement wheel to impart a backspacing movement to said escapement wheel.

12. A typewriter comprising a base frame, a platen carriage framemovable into and out of operating position on said base frame,escapement mechanism on said platen carriage frame comprising anescapement wheel, back spacing mechanism on said `main fra-me comprisinga Contact member for engaging said escapement wheel, means for holdingsaid Contact member in position to cooperate with said escapement wheelbut out of the path thereof when said platen carriage frame is inoperating position, and mechanism for moving said contact member intoengagement with a tooth of said escapement wheel and subsequentlyrotating said member to impart a back spacing movement to saidescapement wheel. v

13. A typewriter having a foldable platen carriage frame, an escapementwheel mounted on said frame, a main frame for supporting said platencarriage frame, and back spacing mechanism arranged to operate directlyon said escapement wheel when said platen carriage frame is in operatingposition.

In testimony whereof I havev signed my name to this specification onthis 22nd day of August, A. D. 1921.

OTTO A. HOKAN SON.

